Threaded Insert for Use with Archery Arrows and Crossbow Bolts

ABSTRACT

Inserts for coupling a broadhead and an arrow shaft or a crossbow bolt, wherein an internal thread pattern in the tube is different from an external thread pattern at an end of the broadhead.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 62/293,440 filed Feb. 10, 2016, the entirety of which is hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

TECHNICAL FIELD

Non-limiting exemplary embodiments of the present disclosure relate to threaded inserts for use with archery arrows and crossbow bolts and, more particularly, to threaded inserts having a threadform different from a corresponding threadform of an end portion of a broadhead.

BACKGROUND

The cross-sectional shape of a thread is called its form or threadform which, for example, may be square, triangular, trapezoidal or other geometrical shape. The terms form and threadform generally refer to design aspects of the thread such as its cross-sectional shape, pitch, and diameters.

In archery, an insert is a component or apparatus that is configured to be at least partially introduced into or inside an opening at an end of an arrow shaft or crossbow bolt. Generally, the inserts have a standardized internal threadform that are paired or matched with a corresponding standardized external threadform at an end portion of a broadhead. During use, the force of impact and/or vibrations induces a generally axial load on the threaded interface of the insert and the broadhead. Consequently, the inserts and broadheads can become loose and disengage.

Therefore, it is desirable to provide inserts and broadheads configured to mitigate or eliminate the force of impact and/or vibrations.

SUMMARY

A non-limiting exemplary embodiment of an insert for coupling a broadhead and an arrow shaft includes a tube having a threaded portion having an internal thread pattern configured for threadably engaging a threaded end of a broadhead, wherein the internal thread pattern of the tube is different from an external thread pattern on the threaded end of the broadhead and at least a portion of the tube is disposed within an opening at an end of the arrow shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a non-limiting exemplary embodiment of an insert for an arrow shaft or crossbow bolt;

FIG. 2 is a cross-sectional view of the insert of FIG. 1 configured with a conventional threadform on an internal surface of the insert;

FIG. 3 is a close-up view of the interface between conventional ANSI standard internal and external threads;

FIG. 4 illustrates the interface between a plurality of conventional ANSI standard internal and external threads of FIG. 3;

FIG. 5 is a cross-sectional view along line A-A of the insert of FIG. 1 configured with a non-limiting exemplary embodiment of a specialty threadform on an internal surface of the insert;

FIG. 6 is a close-up view of the specialty threadform illustrated in FIG. 5;

FIG. 7 is a close-up cross-sectional view of the interface between the specialty threadform illustrated in FIG. 6 and the conventional threads at the end of a conventional broadhead;

FIG. 8 is a side view illustration of the installation of the insert of FIG. 5 into an opening at an end of an arrow shaft or crossbow bolt, and the installation of a conventional broadhead in the insert of FIG. 5;

FIG. 9 is a close-up cross-sectional view of the interface between the specialty threadform of the insert of FIG. 5 and the conventional threads at the end of a conventional broadhead;

FIG. 10 is a side view of a non-limiting exemplary embodiment of an insert configured to fit entirely within the shaft of an arrow or crossbow bolt;

FIG. 11 is a cross-sectional view along line B-B of the insert of FIG. 10 having an internal surface configured with the specialty threadform illustrated in FIG. 6;

FIG. 12 is a cross-section view illustrating the threaded internal surface of the insert of FIG. 10 configured with the specialty threadform illustrated in FIG. 6;

FIG. 13 is a side view of a non-limiting exemplary embodiment of an insert configured to fit half-in half-out in an opening at an end of a conventional arrow shaft or crossbow bolt;

FIG. 14 is a cross-sectional view along line C-C of the insert of FIG. 13 having an internal surface configured with the specialty threadform illustrated in FIG. 6;

FIG. 15 is a cross-sectional view illustrating the threaded internal surface of the insert of FIG. 13 configured with the specialty threadform illustrated in FIG. 6;

FIG. 16 is a close-up cross-sectional view of a portion of the insert illustrated in FIG. 15;

FIG. 17 is a side view of another non-limiting exemplary embodiment of an insert configured to fit half-in half-out in an opening at an end of a conventional arrow shaft or crossbow bolt;

FIG. 18 is a cross-sectional view along line D-D of the insert of FIG. 17 having an internal surface configured with the specialty threadform illustrated in FIG. 6;

FIG. 19 is a cross-sectional view illustrating the threaded internal surface of the insert of FIG. 17 configured with the specialty threadform illustrated in FIG. 6; and

FIG. 20 is a close up cross-sectional view of a portion of the insert illustrated in FIG. 19.

DETAILED DESCRIPTION

One or more non-limiting embodiments are described herein with reference to the accompanying drawings, wherein like elements are designated by like numerals. It should be clearly understood that there is no intent, implied or otherwise, to limit the disclosure to the illustrated and described embodiments. While multiple exemplary embodiments are illustrated and described herein, variations thereof will become apparent or obvious to person of ordinary skills. Accordingly, any and all variants for providing functionalities and/or characteristics similar to the illustrated and described embodiments are considered as being within the metes and bounds of the instant disclosure.

FIG. 1 is a side view of a non-limiting exemplary embodiment of an insert 100 used in a conventional arrow or crossbow bolt. In some embodiments, the insert 100 includes a lip portion 102. FIG. 2 is a cross-sectional view of an insert 200 having an internal surface configured with conventional threads. In all other aspects, the insert 200 is substantially similar to the insert 100. In certain embodiments, the insert 100 includes an internal bore such as that illustrated by the numeral 202 in FIG. 2. The insert 200 is illustrated having the conventional threads 204 extending away from an end of the bore 202 to an end of the insert 200. Generally, the internal bore 202 is configured to receive the shaft portion of a conventional broadhead, and the threads 204 are configured to receive and engage with the threaded end portion of the conventional broadhead.

FIG. 3 illustrates a theoretical profile of a conventional International Organization for Standardization (ISO) metric or Unified Thread Standard (UTS) thread for an internal thread (e.g., a nut) and an external thread (e.g., a bolt). The UTS is maintained by the American Society of Mechanical Engineers (ASME) and the American National Standards Institute (ANSI). While ISO and UTS are different standards, both define a substantially similar geometry, albeit with different dimensions.

In FIG. 3, P represents the thread pitch, H represents the thread height, D_(maj) represents the major diameter, D_(min) represents the minor diameter, and D_(p) represents the effective pitch diameter, as those terms are understood by persons skilled in the art. In some embodiments, the externally threaded end 710 of the broadhead 808 (see FIG. 8) is defined by the ISO metric or by the UTS thread geometry as shown in FIG. 3. Generally, the profiles of both the internal thread 302 (e.g., a nut) and the external thread 304 (e.g., a bolt) do not cross or transgress the theoretical profile. As such, the dimensions of the external threads 304 will be less than or equal to the dimensions of the theoretical profile, and the dimensions of the internal threads 302 will be greater than or equal to the dimensions of the theoretical profile. In practice, tolerances and allowances are provided in the basic profile by rounding the internal and external threads 302 and 304, respectively, at the locations illustrated in FIG. 3.

FIG. 4 illustrates the interface between a conventional ANSI standard internal threads 204 and the conventional threads at an end of a conventional broadhead. In some embodiments, the threads 204 include internal thread roots 206, 208, 210 and 212, and thread flanks 214, 216, 218, 220, 222, 224 and 226. Each thread flank 214, 216, 218, 220, 222, 224 and 226 is inclined (or angled or sloped) at an angle of approximately 60 degrees from a line parallel to the major axis of the threads 204. Threaded flanks 216 and 218 meet at crest 232, flanks 220 and 222 meet at crest 228, and flanks 224 and 226 meet at crest 230.

FIG. 5 is a cross-sectional view of a non-limiting exemplary embodiment of an insert 300 along line A-A of the insert 100 of FIG. 1. In some embodiments, the insert 300 is configured with a non-limiting exemplary embodiment of a specialty threadform 240 extending away from an end of the bore 202 to an end of the insert 300. In all other aspects, the insert 300 is substantially similar to the insert 100. In certain embodiments, the specialty threadform 240 is a SPIRALOCK® threadform having a unidirectional internal threadform which mates with the conventional external threads on a bolt of a shaft such as, for example, the conventional external threads at the threaded end 710 of the conventional broadhead 808 (see FIG. 8).

FIG. 6 is a close-up view of the SPIRALOCK® specialty threadform 240 illustrated in FIG. 5. In some embodiments, the specialty threadform 240 includes thread roots 656, 658, 660 and 662 that generally correspond to the thread roots 206, 208, 210 and 212 of the conventional threads 204 illustrated in FIG. 4. In certain embodiments, the specialty threadform 240 includes thread flanks 676, 678, 680 and 682 that generally correspond to the thread flanks 226, 222, 218 and 214 of the conventional threads 204 illustrated in FIG. 4. As with the thread flanks 226, 222, 218 and 214, each thread flank 676, 678, 680 and 682 is inclined (or angled or sloped) at an angle of approximately 60 degrees from a line parallel to the major axis of the threads of the specialty threadform 240. In some embodiments, the specialty threadform 240 includes wedge ramps 602, 604, 606 and 608, each of which is inclined (or angled or sloped) at an angle of approximately 30 degrees from a line parallel to the major axis of the specialty threadform 240. In certain embodiments, each wedge ramp, e.g., the wedge ramp 608, intersects a corresponding thread flank, e.g., the thread flank 616, at a point, e.g., point 618. In some embodiments, the length of the thread flank, e.g., the distance between points 618 and 620, is approximately one-half the distance between points 306 and 308 of the thread flank 216 shown in FIG. 3. In certain embodiments, the distance d232 shown in FIG. 4 is slightly greater than distance d684 shown in FIG. 6.

FIG. 7 is a close-up cross-sectional view illustrating the interface between the threads of the SPIRALOCK® specialty threadform 240 and the conventional threads, e.g., the external threads at the threaded end 710, of the conventional broadhead 808. As will be apparent to persons of ordinary skills, the specialty threadform 240 is different from the threadform of the conventional threads at threaded end 710. FIG. 7 illustrates a non-limiting exemplary embodiment wherein the specialty threadform 240 and the conventional threadform of the threaded end 710 are not complementary. Consequently, the crests 702, 704, 706 and 708 of the conventional threads at the threaded end 710 are wedged with a relatively large force against the corresponding wedge ramps 602, 604, 606 and 608 of the specialty threadform 240. As a result, lateral movement of the threaded end 710 and the specialty threadform 240 relative to each other, which movement normally results in the loosening of the engagement between the two, is mitigated.

More particularly, in some embodiments, the wedge ramps 602, 604, 606 and 608 permit the threaded end 710 to spin freely relative to the thread flanks 610, 612, 614 and 616 until a predetermined clamp load is applied on the threaded end 710. Generally, the clamp load is a compressive load induced in the directions indicated by arrows 902 and 904 (see FIG. 9) as the threaded end 710 of broadhead 808 is tightened into the insert 300, and the engagement portion 804 of the broadhead 808 contacts the lip portion 102 of the insert 300. At that point, the crests 702, 704, 706 and 708 of the conventional threads at the threaded end 710 are drawn tightly against the wedge ramps 602, 604, 606 and 608 of the specialty threadform 240. Consequently, the radial clearances between the crests and the wedge ramps are eliminated or substantially reduced, and a continuous spiral line contact exists along the entire length of the thread engagement between the specialty threadform 240 and the threaded end 710. The continuous line contact enables the distribution of the clamp force evenly over the entirety of the engaged portion of the specialty threadform 240 and threaded end 710. Consequently, there is a substantial improvement in the integrity of the engagement between the specialty threadform 240 and the threaded end 710. The induced clamp load in the directions indicated by the arrows 902 and 904 distributes the compressive load in a substantially radial direction, as opposed to a more axial direction. Consequently, the threaded engagement between the specialty threadform 240 and the threaded end 710 is further enhanced. As such, the loosening of the threaded engagement due to vibration and/or slipping between the insert 300 and the threaded end 710 of the broadhead 808, e.g., with repeated use, is eliminated or significantly reduced.

FIG. 8 is a side view illustration of the installation of the insert 300 into an opening at an end of an arrow shaft or crossbow bolt 806, and the installation of a conventional broadhead 808 in the insert 300. While the broadhead 808 is used as an exemplary implementation, any point structure, such as a field point, can be similarly secured to the insert 300.

FIG. 9 is a cross-sectional view of the broadhead 808 installed in the insert 300 configured with the specialty threadform 240. The crests 702, 704, 706 and 708 of the external threads of the threaded end 710 are illustrated wedged against the corresponding wedge ramps 602, 604, 606 and 608 of the specialty threadform 240 whereby lateral movement of the threaded end 710 within the insert 300 is eliminated or significantly reduced.

FIG. 10 is a side view of a non-limiting exemplary embodiment of an insert 400 configured to fit entirely within, and inside, an opening at an end of a conventional arrow shaft or crossbow bolt 806. In some embodiments, the insert 400 will generally be located interior to and flush with the inside surface of the arrow shaft or crossbow bolt 806. FIG. 11 is a cross-sectional view along line B-B of the insert 400 of FIG. 10 illustrating the SPIRALOCK® specialty threadform 240. FIG. 12 is a cross-sectional view illustrating the threaded internal surface of the insert 400 configured with the SPIRALOCK® specialty threadform 240.

FIG. 13 is a non-limiting exemplary embodiment of an insert 500 configured to fit half-in half-out of an arrow shaft or crossbow bolt. In some embodiments, such half-in half-out inserts 500 facilitate the use of standard size conventional broadheads 808 or arrow tips with arrow shafts having inside diameters smaller than the standard arrow shafts. In certain embodiments, the half-in half-out insert 500 includes a ribbed portion 1202 configured for securement within an opening at an end of an arrow shaft or crossbow bolt 806. In some embodiments, the portion 1204 of the insert 500 has a larger outside diameter that generally corresponds to and interfaces with the outside diameter of the arrow shaft or crossbow bolt 806. The internal surface of the portion 1204 of the insert 500 is configured with the SPIRALOCK® specialty threadform 240, illustrated in FIG. 6, for receiving the threaded end 710 of the conventional broadhead 808. FIG. 14 is a cross-sectional view along line C-C of the insert 500 illustrating the specialty threadform 240 on the internal surface of the insert 500. FIG. 15 is a cross-sectional view illustrating the threaded internal surface of the insert 500 having the SPIRALOCK® specialty threadform 240. FIG. 16 is a close-up cross-sectional view of a portion of the insert 500. In some embodiments, a generally circumferential wall 1302 of the insert 500 slides over the external surface of the arrow shaft or crossbow bolt 806. In certain embodiments, the circumferential wall 1302 is configured to form a friction fit with the arrow shaft or crossbow bolt 806. That is, the inside diameter 1304 of circumferential wall 1302 in conjunction with the forward portion 1306 of the ribbed portion 1202 form a friction fit with the arrow shaft or crossbow bolt 806 when placed over and pressed snugly against the arrow shaft or crossbow bolt 806. In some embodiments, the circumferential wall 1302 is glued to the external surface of the arrow shaft or crossbow bolt 806 to further secure the insert 500 in place.

FIG. 17 is a side view of another non-limiting exemplary embodiment of an insert 600 configured to fit half-in half-out in the arrow shaft or crossbow bolt 806. In some embodiments, the insert 600 includes ribbed portion 1702 that fits into an opening at an end of the arrow shaft or crossbow bolt 806. A circumferential portion 1704 of insert 600 interfaces with a circumferential portion of the arrow shaft or crossbow bolt 806. In some embodiments, the insert 600 does not include a generally circumferential wall, such as circumferential wall 1502 of the insert 500. FIG. 18 is a cross-sectional view along line D-D of the insert 600 illustrating the SPIRALOCK® specialty threadform 240 on an internal surface of the insert 600. FIG. 19 is a cross-sectional view illustrating the internal surface of the insert 600 having the specialty threadform 240. FIG. 20 is a close-up cross-sectional view of a portion of the insert 600.

In view thereof, modified and/or alternate configurations of the non-limiting exemplary embodiments described herein may become apparent or obvious to persons of ordinary skill. All such variations are considered as being within the metes and bounds of the instant disclosure. For instance, while reference may have been made to particular feature(s), function(s) and/or characteristic(s), the disclosure is considered to also encompass equivalents and embodiments configured for functioning and/or providing functionalities similar to those illustrated and described herein. Accordingly, the spirit, scope and intent of the instant disclosure embraces all variations and alternatives. The metes and bounds of the disclosure is solely defined by the appended claims and any and all equivalents thereof. 

What is claimed is:
 1. An insert for coupling a broadhead and an arrow shaft, the insert comprising a tube comprising a threaded portion having an internal thread pattern configured for threadably engaging a threaded end of a broadhead, wherein the internal thread pattern of the tube is different from an external thread pattern on the threaded end of the broadhead; and at least a portion of the tube is disposed within an opening at an end of the arrow shaft.
 2. The insert of claim 1, wherein the internal thread pattern comprises: a first thread flank disposed in a first direction at a first angle relative to a line parallel to an axial centerline of the insert; and a second thread flank disposed in a second direction at a second angle relative to the line parallel to the axial centerline of the insert, the second thread flank comprising a wedge ramp disposed in a third direction at a third angle relative to the line parallel to the axial centerline of the insert.
 3. The insert of claim 2, wherein the first and the second angles are substantially equal; and the third angle is different from the substantially equal first and the second angles.
 4. The insert of claim 3, wherein the first and the second angles each are approximately 60 degrees; and the third angle is approximately 30 degrees.
 5. The insert of claim 3, wherein the external thread pattern comprises a pair of thread flanks each disposed at an angle substantially equal to the substantially equal first and the second angles
 6. The insert of claim 2, wherein an angle between the first thread flank and the wedge ramp is approximately 90 degrees; and an angle between the second thread flank and the wedge ramp is approximately 30 degrees.
 7. The insert of claim 2, wherein the first thread flank and the wedge ramp intersect at a thread root on an internal surface of the tube.
 8. The insert of claim 7, wherein the second thread flank and the wedge ramp intersect at a location opposite the thread root.
 9. The insert of claim 2, wherein the first and the second thread flanks are adapted to receive a thread of the external thread pattern.
 10. The insert of claim 9, wherein the first and the second thread flanks and the external thread pattern have complementary profiles.
 11. The insert of claim 9, wherein the external thread pattern comprises at least one thread flank, wherein at least a portion of a surface of the at least one thread flank contacts at least a portion of a surface of the wedge ramp.
 12. The insert of claim 2, wherein the insert comprises: a plurality of the first thread flanks; a plurality of the second thread flanks; and a plurality of wedge ramps.
 13. The insert of claim 1, wherein the internal thread pattern comprises a unidirectional threadform.
 14. The insert of claim 13, wherein the unidirectional threadform is configured to engage with a conventional threadform.
 15. The insert of claim 14, wherein the unidirectional threadform comprises a plurality of wedge ramps; and the conventional threadform comprises a plurality of crests; wherein, the plurality of the wedge ramps and the plurality of the crests are wedged together with a relatively large force.
 16. The insert of claim 15, wherein radial clearances between the plurality of wedge ramps and the plurality of crests is substantially reduced.
 17. The insert of claim 15, comprising a substantially continuous contact between the internal thread pattern and the external thread pattern.
 18. The insert of claim 14, wherein a threaded engagement between the unidirectional threadform and the conventional threadform substantially reduces lateral movement between the internal and the external thread patterns. 